Latex paint compositions have captured a significant portion of the indoor and outdoor paint market because they have several advantages compared with the organic solvent type. These advantages include easier clean up, little or no air pollution, and a reduced fire hazard. Two types of emulsions commonly used in formulating latex paints include the all acrylic system, e.g., the systems using copolymerized methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate with small proportions of acrylic acid, etc., and vinyl acetate formulations using vinyl acetate in combination with a small proportion of a lower alkyl acrylate, e.g., 2-ethylhexyl acrylate, methyl methacrylate, butyl acrylate, or dibutyl maleate. Vinyl acetate-acrylic copolymer systems have been utilized in formulating interior flat, semi-gloss paints and exterior house paints. Vinyl acetate-butyl acrylate lattices result in paint films with excellent toughness, scrub resistance and durability, while the vinyl acetate-dibutyl maleate emulsions have good abrasion resistance and flexibility as well as durability.
Paints typically include a pigment composition to achieve the desired color and hiding power of the paint. Many interior and exterior paints include hiding white pigments. Other tints and colors can be mixed with the white pigments to obtain various colored paints. The pigments used in the paint can include inorganic and organic pigments, pigment lakes, insoluble dyes and other durable coloring matter. While the pigmentation of the paint can be solely from prime pigments, it is economically impractical to use solely prime pigments at the indicated high pigment volume concentration. As such, it is common that the pigment in the paint includes a hiding prime pigment and a pigment extender. Common pigment extenders include calcium carbonate, gilders whiting talc, barytes, magnesium silicates, aluminum silicates, diatomaceous earth, china clay, asbestine, silica and mica. The relative proportions of the prime white pigment and the pigment extender in the pigment mixture may be varied widely, but usually the hiding prime pigment is present at a pigment volume concentration which provides the desired paint covering power or hiding and the extender pigment is present in an amount which provides the paint with the desired total pigment volume concentration.